Monitoring the vadose zone in fractured tuff, Yucca Mountain, Nevada

Conference · Tue Dec 31 04:00:00 EST 1985

OSTI ID:59850

Montazer, P; Weeks, E P; Thamir, F; Yard, S N; Hofrichter, P B

Unsaturated tuff beneath Yucca Mountain, Nevada, is being evaluated by the US Department of Energy as a host rock for a potential repository for high-level radioactive waste. As part of the Nevada Nuclear Waste Storage Investigations Project of the US Department of Energy, the US Geological Survey has been conducting hydrologic, geologic, and geophysical investigations at Yucca Mountain and the surrounding region to provide data evaluation of the potential suitability of the site. Hydrologic investigations of the unsaturated zone at this site were started in 1982. A 17.5-inch- (44.5-centimeter-) diameter borehole (USW UZ-1) was drilled by the reverse-air vacuum-drilling technique to a depth of 1269 feet (387 meters). This borehole was instrumented at 33 depth levels. At 15 of the levels, 3 well screens were embedded in coarse-sand columns. The sand columns were isolated from each other by thin layers of bentonite, columns of silica flour, and isolation plugs consisting of expansive cement. Thermocouple psychrometers and pressure transducers were installed within the screens and connected to the data-acquisition system at the land surface through thermocouple and logging cables. Two of the screens at each level were equipped with access tubes to allow collection of pore-gas samples. In addition to these instruments, 18 heat-dissipation probes were installed within the columns of silica flour, some of which also had thermocouple psychrometers. 20 refs., 13 figs., 2 tabs.

• Research Organization: Geological Survey, Denver, CO (United States); Goodson and Associates, Inc., Denver, CO (United States); Holmes and Narver, Inc., Las Vegas, NV (United States)
• DOE Contract Number: AI08-78ET44802
• OSTI ID: 59850
• Report Number(s): CONF-8511172--8; ON: DE86008850
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
58 GEOSCIENCES
BOREHOLES
DATA ACQUISITION
GEOPHYSICAL SURVEYS
HIGH-LEVEL RADIOACTIVE WASTES
HYDRAULIC CONDUCTIVITY
MOISTURE
MOISTURE GAGES
NEUTRON LOGGING
PERMEABILITY
POROSITY
POTENTIAL ENERGY
PSYCHROMETRY
RADIOACTIVE WASTE DISPOSAL
ROCK DRILLING
TUFF
UNDERGROUND DISPOSAL
YUCCA MOUNTAIN
Yucca Mountain Project